The biosynthesis of menaquinone (vitamin K2) will be studied in bacteria, particularly E. coli and Mycobacterium phlei. The role of 2- ketoglutarate and its addition to shikimate will be investigated by conventional tracer techniques and by the aid of a gas chromatography- mass spectrometer-proportional counting combination. Intermediates will be isolated where possible and structures will be determined for them: in some experiments, the use of inhibitors to cause accumulation of intermediates will be explored. Possible intermediates will be examined to determine whether they can substitute for the vitamin K requirement of the strict anaerobe, Bacteroides melaninogenicus. Finally, individual reactions and their mechanisms will be examined by use of cell-free enzyme systems.